This invention relates generally to automatic information retrieval, and particularly toward a telephone number information system which requires minimum human operator intervention.
A prior art automatic telephone information system is disclosed in U.S. Pat. No. 3,242,470 to Hagelbarger et al. In that system, the entire contents of a telephone directory are entered, in digitally encoded form, into a computer memory. For retrieval purposes, the directory contents are summarized by coarse indices, each of which covers 200 fine indices. This coarse index is used for an initial search operation which narrows the desired memory location to 1/200 of the total directory. Each of the 200 groups of entries is further subdivided into 200 finer parts represented by fine indices for a further level of searching. Finally, each of the 200 finer parts may be further sub-divided into 50 much finer groups by finer indices. In this way, searching proceeds until it is determined at what address in memory the desired entry will be found. The coarse and fine searching is all done on an alphabetical basis. In case the information supplied to the computer as an inquiry lacks completeness, as is frequently true, the Hagelbarger system does not generate the correct subscriber information (telephone number).
If the inquirer knows the complete and correct spelling of the desired subscriber's name, and if the alphabetical coarse and fine searching discloses the memory address of the desired entry, the next step in the Hagelbarger system is to translate an entire block of telephone information entries found at that memory address into video form, and to display the entire block of information on a video screen for inspection by the information operator. This procedure involves complicated and expensive electronic hardware, and the operator must still read through the displayed block of information.
Moreover, in order to make the print large enough to be read easily on the video screen, only one-eighth of a block of information contained in one memory address is displayed at any time on the video screen. The operator must then manually scan the video "window" across the irrelevant portions of the block of information until the relevant one-eighth portion is located before the operator can begin searching for the specific information desired.
One difficulty in prior art automatic telephone number information service is due to the inaccuracy of the requester's knowledge of the subscriber whose telephone number he is seeking. This difficulty is aggravated by the requirement of rapid, random access of information based on an inaccurate request.
In practice, I have found that the coincidence rate between raw information in an inquiry and that in a directory on the basis of coincidence of each character is shown below.
Name . . . about 30%
Address (Residence Location) . . . about 13%
Occupation . . . about 4%
Further, I have found that simultaneous coincidence of name, address, and occupation was about, at most 13%.
Thus, the greater the number of descriptors (keyword items), the lower the answerable rate when the input information is inaccurate.
In Hagelbarger, only the surname is used for the retrieval index. However, in his system, the number of answers becomes larger inversely proportional to the degree to which the index is simplified so that the operator must confront a larger block of data. This requires increased operator intervention.
In some conventional prior art systems, a "randomizing method" is used for random access using spoken language. The "randomizing method" breaks down the word pattern into random numerals for memory address by a predetermined mathematical operation. Since the letters in a human name are in a statistically uneven distribution, the result of the randomizing method is insufficient to achieve true random distribution of characters. This gives rise to superposition of entries at common locations. Therefore, in the prior art, alphabetical arrangement in regular sequence of file entries is not suitable for direct access retrieval.
Accordingly, one object of the present invention is to provide a new and improved automatic telephone information system.
Another object of the present invention is to provide an automatic telephone information system which does not require digital-to-video conversion equipment.
Another object of the present invention is to provide an automatic telephone information system which will supply a correct answer even when the inquirer does not know the subscriber's exact name, is not sure of the proper description of the subscriber's business, or is not sure of the address.
Another object of the present invention is to provide an automatic telephone information system employing cross-correlation of three independent forms of information, e.g., name, occupation, and address, so as to reduce the number of possible answers that must be considered by the operator.
Another object of the present invention is to provide an automatic telephone information system employing random access file entry, in alphabetical arrangement, without any location gaps or any superposition of entries, and which uses a spoken language index.
Another object of the present invention is to provide a new and improved automatic telephone information system which is faster, requires less operator effort, and compensates for the operator's own errors, as well as the inaccuracy or indefiniteness of the inquirer's information.